This glitch has been going on for a few weeks now. Under the item price, instead of saying "free postage" or "postage $7.20", it says "will post to Australia" and when you click on the postage tab, it says postage can't be calucated, please enter a valid postcode. I'm having to send invoices to nearly every buyer as they can't pay.

It also means that free postage items aren't showing as free postage when the buyer looks at it. There is no free postage banner across the photo. 

If you send the buyer an invoice, they should be able to pay with free postage.